GARDENING : Getting a Handle on Ways to Help Plants Make It Through Rainy Days

As you look outside this wet winter, you may wonder if your landscape will ever be the same. After all, how much water can the average yard take? The good news is that most plants can withstand heavy rain and will often benefit from a little excess water.

“Those plants that survive the heavy rains will probably be better off,� says Steve Hollister, manager of Armstrong Garden Center in Irvine. “Rain isn’t laden with harmful salt like our ground water. Instead, it leaches salt out of the soil. When the rain quits, plants generally take on a healthy attitude.�

Though rainwater may be good for plants in the long run, the heavy amount of water we’ve received in recent weeks has changed Orange County garden conditions.

The following tips will help you adjust your gardening strategy to deal with the unusually wet weather and alert you to conditions that may arise because of soggy soil.

Immediate effects. Heavy rains can cause a number of problems, including the following:

* Leaves may have water damage, which consists of yellowing foliage, especially at the bottom of plants.

* Expect leaf spot, a moisture-loving fungus common in wet weather that causes red, brown, yellow or black disease spots on leaves.

* Some flower blooms, such as camellias and azaleas, will rot because of fungus before or after opening. Other flowers such as pansies will easily become waterlogged and suffer from crown rot.

* Various grasses, such as bluegrass and rye, and to a more limited extent, fescue, may turn orange from rust disease.

* Citrus trees whose root systems have been damaged by over-saturation will experience June fruit drop. This isn’t very serious, however, and the remaining fruit is actually larger and sweeter.

* Don’t be surprised if sap is oozing from the bark of your deciduous fruit trees. This is a tree’s natural way of relieving pressure from too much water and does not cause any long-term problems.

* If you fertilized in the last month or so with anything other than a time-release fertilizer, it was probably washed away by the rains. Rather than fertilizing again now, experts suggest waiting until your plants begin leafing out in spring. Otherwise, you may overstimulate the plants and they will produce too much tender new growth.

Long-term effects. In many cases only time will tell if a plant has suffered permanent rain damage. Plants that receive too much water, especially those sitting in standing water, will lose roots due to oxygen deprivation, says Gary Matsuoka, owner of Laguna Hills Nursery in Lake Forest. Though these plants may continue to look healthy while the weather remains cool, as soon as we get our first heat wave, they may die. This occurs because their limited root systems can’t provide enough water to the foliage.

Drainage problems. If you have a drainage problem in any area of your yard, the rain will show it. Identify any problem areas by looking for standing water, which can do great damage to your landscape.

“Standing water excludes air from plant roots, and roots need air as much as they need water,� Hollister says.

In minor situations, Hollister and other experts suggest digging trenches to drain water away from plants. Just be certain not to damage roots when digging.

You can avoid water damage in the future by planting on mounds.

If you’re having problems with erosion, try using mulching to control it. Mulching will more readily absorb rainwater than the soil surface.

For more serious situations where the back yard resembles a lake, you should install an underground drainage system, or you risk losing much of your landscape in future rains, says John Kabashima, environmental horticulture adviser for the University of California Cooperative Extension. He is based at the South Coast Research and Extension Center in Irvine.

Unstable Trees. When the soil is soggy, trees lose their anchor and sometimes fall, especially if it is windy. The bad news is once an established tree uproots, it’s usually not savable, Matsuoka says.

Unfortunately, there is no sure way to know if a tree is going to fall over. There are things you can do to minimize the likelihood of a tree uprooting.

The first line of defense against losing a tree is ensuring that it isn’t top heavy.

“A thick treetop acts like the sail on a ship,� Hollister says. “Wind hitting this sail is a very powerful force that will tear the tree right down.�

Most trees should have been thinned in late fall or early winter, but you can still thin many trees now, providing that you do so in moderation. The goal is to allow wind to flow through the branches.

You can also guy-wire trees, which will keep them steady in wet soil, Matsuoka says. Many experts suggest having this professionally done.

Soil condition. Resist the urge to begin planting until the soil has dried out. Don’t work wet soil, especially clay. Working wet clay soil compacts it and depresses air out, which damages the soil structure. When it dries, you’ll end up with very hard clods.

Wait until clay soil no longer sticks to a garden spade before planting. The soil should be crumbly down to the root zone of the plant you’re planting.

Because of differences in soil type throughout a yard, it is common to be able to plant one area of the yard sooner. Sandy and loamy soil will dry out more quickly than clay, as will raised beds.

Bare-root plants. Although soggy soil may prevent you from planting, now is a great time to select from the wide variety of inexpensive bare-root deciduous fruit trees and roses found at your local nursery. Bare-root plants can be stored for several weeks until the soil is workable.

Most experts suggest storing bare-root plants outdoors where they will stay moist. Kabashima recommends removing bare-root plants from their packaging, placing them in a bucket and covering them with the sawdust they came in. Then keep them moist. (When planting, remove most of the sawdust, as this will rob the soil of nitrogen.)

Hollister suggests storing bare-root plants in the bags they came in and making sure to keep them moist. If you can’t find a good area outside your home, the garage can also be used to store them.

What you can do. Good gardening chores to do now include the following:

* Prune deciduous fruit trees by the end of January but be careful not to slip on muddy ground.

* Now is the time to spray deciduous fruit trees and roses with a dormant oil spray, which will destroy diseases and organisms overwintering on these plants. Just make sure to spray when you’re expecting a day or two of dry weather.

* When the soil is wet it’s a great time to do the otherwise back-breaking chore of weeding. Weeds slide right out of wet soil.

* If it’s pouring outside, and you’re in the gardening mood, do like the farmers do. Peruse seed catalogues and plan your spring garden.